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383 Build Parts

caleb22

caleb22

1/2 ton status
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I'm planning a 383 swap in my 76 to yank out the tired Gen II 350, will reuse it in another project. No LS for me now, want to stay low complexity and get it done quickly. Goal is higher torque, economy, overall performance for a sometimes DD. No wheeling, TH350 trans.

I'm buying a new short block because I can't find a used block and no local machine shops rated well. May need to go to Charlotte for the 350 deck and hone.

Would like some cylinder head and intake advice and to know what you guys think of the cam specs, etc.

Maybe Trick Flow heads and a single plan edelbrock intake? 91 Octane preferred, maybe a 64cc chamber?


ATK SP52 383 short block (cost was tad more than 350 block)
(4 Bolt Main, 1pc Seal, Bore/Stroke: 4.040 x 3.750, Crankshaft Scat Nodular Iron 3.750" Stroke Externally Balanced Rear/Internal Front, Connecting Rods Scat 4340 Forged I Beam 5.700", ARP 8740 Bolts, Pistons Forged 3.7cc Flat Tops, Moly Rings, Compression Ratio: 58cc=11.9:1/64cc=11.0:1/70cc=10.3:1)

COMP Cams K12-409-8
Cam Style: Hydraulic roller tappet
Basic Operating RPM Range: 1,000-5,000
Intake Duration at 050 inch Lift: 206
Exhaust Duration at 050 inch Lift: 210
Duration at 050 inch Lift: 206 int./210 exh.
Advertised Intake Duration: 258
Advertised Exhaust Duration: 262
Advertised Duration: 258 int./262 exh.
Intake Valve Lift with Factory Rocker Arm Ratio: 0.458 in.
Exhaust Valve Lift with Factory Rocker Arm Ratio: 0.458 in.
Valve Lift with Factory Rocker Arm Ratio: 0.458 int./0.458 exh.
Lobe Separation (degrees): 111
Grind Number: X4258HR
Outside Diameter of Outer Spring (in): 1.254 in.
 
Based on an episode of Engine Masters that I watched where they compared a dual to a single...but I'm open to suggestions or experience for sure :)
 
My concern would be the loss of low end. The exception may be using EFi, there is some debate that a single plane may be different there


What cylinder head would you use? That choice would dictate if that cam is good
 
Some type of vortec head. Also, if possible I might do Holley Sniper EFI if I can run some return lines back to the tank and swap the tank too.
 
Ok. Keep in mind that lift cam is borderline on vortec heads due to valve train issues. And dumping a bunch of money into factory vortec heads may not be worth it

The vortec is also a different intake then the old style. If your going Sniper, the single plane may do you well, but I’d avoid the large port or high volume ones for racing because it lowers the port velocity
 
caleb22 said:
I'm planning a 383 swap in my 76 to yank out the tired Gen II 350, will reuse it in another project. No LS for me now, want to stay low complexity and get it done quickly. Goal is higher torque, economy, overall performance for a sometimes DD. No wheeling, TH350 trans.

I'm buying a new short block because I can't find a used block and no local machine shops rated well. May need to go to Charlotte for the 350 deck and hone.

Would like some cylinder head and intake advice and to know what you guys think of the cam specs, etc.

Maybe Trick Flow heads and a single plan edelbrock intake? 91 Octane preferred, maybe a 64cc chamber?


ATK SP52 383 short block (cost was tad more than 350 block)
(4 Bolt Main, 1pc Seal, Bore/Stroke: 4.040 x 3.750, Crankshaft Scat Nodular Iron 3.750" Stroke Externally Balanced Rear/Internal Front, Connecting Rods Scat 4340 Forged I Beam 5.700", ARP 8740 Bolts, Pistons Forged 3.7cc Flat Tops, Moly Rings, Compression Ratio: 58cc=11.9:1/64cc=11.0:1/70cc=10.3:1)

COMP Cams K12-409-8
Cam Style: Hydraulic roller tappet
Basic Operating RPM Range: 1,000-5,000
Intake Duration at 050 inch Lift: 206
Exhaust Duration at 050 inch Lift: 210
Duration at 050 inch Lift: 206 int./210 exh.
Advertised Intake Duration: 258
Advertised Exhaust Duration: 262
Advertised Duration: 258 int./262 exh.
Intake Valve Lift with Factory Rocker Arm Ratio: 0.458 in.
Exhaust Valve Lift with Factory Rocker Arm Ratio: 0.458 in.
Valve Lift with Factory Rocker Arm Ratio: 0.458 int./0.458 exh.
Lobe Separation (degrees): 111
Grind Number: X4258HR
Outside Diameter of Outer Spring (in): 1.254 in.
Click to expand...

If you are going with that small cam you definitely need the larger chamber heads with that flat top piston. If possible I recommend a dished piston for your setup. In fact SCAT probably makes a setup with the KB hyper pistons in a dish that would suit you better. Your compression (static and dynamic) is going to be too high with that cam and 64 cc heads. You probbaly need 76 cc heads with those pistons.

I would also recommend a slightly larger cam unless you just want an extremely mild driver. I like the fact that you are going with a hydraulic roller, good choice, its worth the cost. Maybe one step higher would suit you well and still give good economy but more power.

If you are going carb I recommend an Edelbrock performer RPM or RPM air-gap dual plane intake manifold. If you are going with the EFI then select a victor Jr or other small single plane.

Do they deck the block to 9.000 or flush with the piston? I would check with feeler gauges, you may need a thinner gasket to get .040-.045 quench.

What is your budget for heads?

Capture.JPG
 
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IF you are set on the ATK brand shortblock (I have zero experience with them and the reviews seem to be hit or miss so I can't say I recommend them), then you would be better off with the SP15 that has 18 cc dish hypereutectic pistons. They are better for a driver that doesn't need forged pistons (lower coefficient of thermal expansion than forged) and the dished piston will give you better compression and potentially higher efficiency with the dish design.

Assuming the 18 cc dish pistons, I would get one of these ~64cc chamber ~180cc intake port heads...(pick your brand, all of these part numbers should have springs good for a hydraulic roller)

Dart SHP #127122
Dart Pro1 #11121112P
Edelbrock RPM #61015
Edelbrock E-tec #60975
Brodix IK #1021005
Brodix RR # 1011004 S

Normally for a street performance 383 build I would suggest the 200 cc heads, but since you want economy and driver before power then I would stick with the 170 -180 range. Then for intake I would say Edlebrock RPM for carb use, or Victor Jr for EFI use. (be aware the E-tec head requires the Vortec style intake bolt pattern, the rest use traditional). The Edelbrock heads are likely the best price, the other two probably make slightly more hp.

For the cam since you want economy before power I would still go up one size for a 210-220 intake duration at .050, and I would look for a little more lift, pushing .500 or so depending on whats available in that duration, the comp Extreme Energy (also in 4x4 with slightly looser LSA) amd Lunati VooDoo are good series to look in. Howards make some decents grinds too and cost competitive. I think your LSA shoudl be around 112 - 114, the higher it is the smoother your idle will be and the flatter your torque curve but possibly with less peak HP. You can also go down to 110 no problem and still have good vacuum with that small duration.
 
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I just checked out comp based on my above recommendations and found this cam that should fit your needs...

http://www.compcams.com/Company/CC/cam-specs/Details.aspx?csid=194&sb=0

if you get the CL08-501-8 it will come with the lifters and you can reuse your old spider and lifter plates with the new 1 piece seal block.

I would recommend upgraded rockers and 1 piece pushrods if it's in the budget.

Ignore the computer controlled, its a small cam(still considerably more power than your initial choice) that should idle well and produce decent power whether you use a carb or EFI. You can go bigger and get more power relatively easily (and I almost always do) but I'm not sure if you will like the idle.

If you combine that cam with the 18cc dish pistons and 64 cc heads you get this...

Capture.JPG
 
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Did you get the 383 all done or are you still in the planning stages?
 
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